CORRESPONDENTS who expect to receive answers to their letters must, m ail cases, sign their names. We have a right to know those who seek, ir, -formation from it ; beside, as sometimes happens, we mai/ prefer to ad dress correstonde)its by mail. SPECIAL NOTE,—This column is designed for the a eneral interest and in struction of our readers, not for gratuitous replies to Questions of a purely business or personal nature. We will publish such inquiries, hovyever-when paid for as advertisemets at ??'?? a line, under the head of Bmi-ness and Personal.' AUreference to back numbers should be by volume and page. ' T. E. K., oi La.—Timber may be rapidly seasoned by steam ing, but it is unnecessary to do it under enormous pressure ; in fact, high pressure, and.consecincntly, high temperature, art' injurious to the wood. Suflicicnt vent should he all0?vcd to keep the steam down to 212 degrees, which is hot enough. The steaming is carried far enough when the sap has been converted into steam and driven out of the wood. ?fe?vdays exposure to the air after taking the timber from the steam box will render the ?????? fit to work. If the operation is performed according to these directions the steaming box need not be very strong ; it should, however, be tight enough to hold the &team, which should, at least the greater part of it, escape as steam, not as water through the vent. W. D., of N. Y.—The first complete electric telegraph of which we have any knowledge, was established in the year 17 )8, between Madrid and Arilnguez, in Bpain, by an electrician named Betancourt. This was, ho?veveG,not at all on the principle of the modern telegraph, as electro-magnetism vas not discovered till 1819. Wheatstone's telegraph ?vas patented in England in June, 1837, and Morse filed his first caveat in Octo ber of the same year. To Morse is undoubtedly due, however, the credit of inventing a telegraphic alphabet which has ever since been univer sally used. J. H., of N. Y.—To japan castings, clean them well from the sand, either in a 'tumbler" or by other convenient means, then dip them in or paint them over with good boiled linseed oil. When the oil has be come moderately dry, put them in an oven and heat them to such a tem perature as will turn the oil blaek without burning. The stove should notbe too hnt at lirst, and the heat should be raised gradually to avoid blistering. The slower the change in the oil is eil'ected the better will be the result. The castings, if smooth at first, will receive a fine black and polished surface by this method. L. B., of Ohio.—Xou do- not inform iis whether you wish to construct your cistcrnabove or belo?V ground. If above ground, a wood en cistern made of good pine answers a good purpose ; if below, brick laid ingoodhydrauliccement, and Emoothly plastered with the same on the inside, answers a good purpose. Of all the filters vre have tried, we like the working of none better than that of gravel and charcoal, efi"ected by passing the water through two casks, oneiilled with fine gravel and the other with coarse charcoal powder. T. B. McC. of Del.—The mineral you send is a poor specimen 01 graphite, or plumbago. It is composed chiefly of carbon, ?vith which impurities, consisting of earthy matters, are mixed. Plumbago is prin cipally used in the manufacture of crucibles and lead pencils, also for electro-plating, polishing stoves, castings, etc. The refining an d prepar ing of the article for usu is ali-unacd with uonelUeiabiu lahor. R. C, of Del.—Wo do not wish to open our columns to the dis cussion you propose. J. B. C, of Mich.—You can set two 60-horse power boilers to run with a single furnace and grate, but the plan ????? not, in our opin ion, be economical. To blow off one of two boilers thus set while the fire was maintained to keep up steam in the other, would be likely to lead to overheating the boiler. We advise building a separate furnace for each. This axn easily be done so as to have the boilers stand side by side as you desire. A. H. S., of Hayti.—The action oi the sour cane juice upon iron pipes in scaling them, is a tUfliculty met with on all plantations. An old plantation engineer informs us that he used, when in Cuba, to scale the pipes by letting cold water into them vhile hot. ??a do not know that this would answer with you. Should it fail wo are not aware of any thing better than the old practice. R. W. of Pa.—"The depth of the artesian well of Oreiiclje, at Paris, is 1,191>; feet. Eespecting the water, it ?vas ascertained that it does not contain the least trace of air, andwasfor that reason considered un fit for use. To obviate this defect, the water descends from the top of a : tower in innumerable threads, ?vhicU exposes it to the air. S. C, of Colorado.—Malachite is brought chieily'from a single mine in the Ural Mountains in Russia, and indicates the near presence of copper. Its value is estimated in veight at about one fourth that of silver. It is not at all probalJle that you have found malachite in your section. H. T., of Mich.—So far as we are aware, the Norwegian cook ing apparatus is not made in this country. It is sold in England to some extent, and appears to be a usefulapparatus for the purpose. \ E. IT. S., of Mass.—Will forcing a cold blast into a chimney above the fire box increase the draft to the same extent and aid in com bustion as much as though forced directly into the fire box below the fuel? —Answer, No. W. p., of Oregon.—Patents have been obtained for sheep-shearing machines, but we are not aware that any of them have yet come into use. The field appears still to be open, S. A. K.jOi Ohio.—We know of no cement that is generally and economically applicable to all cases where iron and stone are to be united.